Mshable have taken a close look at this.
"......This is Just the First Step
With the announcement that American Express, Discover and Visa have all licensed their NFC technologies to Google, the next step is to get the thousands of financial institutions and merchants on-board with an NFC system.
Meanwhile, the NFC space is highly competitive. Visa has its own mobile wallet initiatives, as does American Express and PayPal. We're at an interesting place in the market; we're finally at a point where lots of activity is happening in this space and mainstream adoption seems closer than ever, yet these competing solutions complicate short-term adoption.
The biggest opportunity we see, right now, is for Google Offers. Google Offers as an app is a nice way to browse for deals, specials and coupons. You can clip those offers digitally to Google Wallet and then show the coupons at merchants, whether they are NFC-enabled or not.
The potential for the deal discovery space, especially with the addition of geolocation, is something I have been waiting to see take off for nearly two years. Google is being very cautious to make its experience as low-friction as possible. However, with the right tweaking and perhaps with greater social integration, a la Google Places and Google+, this component could really separate Google from the pack.